.abs {
    position: absolute;
}

.fix {
    position: fixed;
}

.postl {
    top: 0;
    left: 0;
}

.postr {
    top: 0;
    right: 0;
}

.posbl {
    bottom: 0;
    left: 0;
}

posbr {
    bottom: 0;
    right: 0;
}

.posc {
    @extend .abs;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.fixfull {
    @extend .fix;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
}

.rel {
    position: relative;
}

.absfull {
    @extend .abs;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
}